基于邻近原则的应用层组播实验研究*

提出了一个基于邻近原则的应用层组播系统,其覆盖网络由参与节点求得自身网络坐标之后,根据网络坐标基于邻近原则聚类形成。通过基于网络测量数据的仿真和PlanetLab真实网络环境中的实际测试,证明了基于该覆盖网络结构的应用层组播系统在性能指标上优于当前普遍应用的基于其他结构的覆盖网络的系统。在构建覆盖网络过程中考虑节点在网络中的位置分布等因素将能够提高基于该覆盖网络的应用层组播性能。     

基于高速网络的入侵检测系统研究

目前基于网络的入侵检测系统已经无法适应高速增长的网络速度,因此研究在高速以太网上实现的网络入侵检测系统是十分必要的。介绍了两种基于高速网络的入侵检测系统。一种是基于FPGA的高速网络入侵检测系统,另一种是基于数据分流的高速网络入侵检测系统。     

基于Snort的网络入侵防御探究

为了研究基于Snort的网络入侵防御,文章首先介绍了入侵防御体系工作原理,再之介绍了网络入侵检测技术,主要包括基于网络的入侵检测系统以及基于主机的入侵检测系统,最后详细研究了基于Snort的网络入侵设计。文章的研究可以作为基于Snort的网络入侵防御设计过程中的参考。     

基于虚拟现实技术的网络学习的应用研究

随着网络技术的发展,基于网络的网络学习已成为人们关注的热点。该文就如何通过虚拟技术,增加网络学习的实用性,从而适应基于网络的网络学习的需要,提高教学质量和学者学习的兴趣。     

基于伪孪生网络双层优化的对比学习

目前,基于伪孪生网络的对比学习算法使用各种组件以获得最优学生网络,但忽略教师网络在下游任务中的表现,因此,文中提出基于伪孪生网络双层优化的对比学习,促进学生网络和教师网络相互学习,获得最优教师网络.双层优化策略包括基于近邻优化的学生网络优化策略和基于随机梯度下降的教师网络优化策略.基于近邻优化的学生网络优化策略让教师网络成为约束项,帮助学生网络更好地向教师网络学习.基于随机梯度下降的教师网络优化策略求解近似教师网络,梯度更新教师网络.在5个数据集上的实验表明,文中算法取得较高的k-NN(k=1)分类精度和线性分类精度,特别在批次大小较小时,优势较大.     

基于兴趣的P2P网络应用研究

本文提出一种基于兴趣的P2P向络架构,该架构结合了非结构化网络和兴趣网络.文章基于兴趣网络的社区结构改进搜索机制,并且基于兴趣网络提出应用于P2P网络的基于用户和基于项目的资源推荐服务.     

基于IXP1200网络处理器的边缘路由器实现

基于网络处理器的路由器开发是一个热点。文中介绍了基于网络处理器的路由器体系结构,分析了IXP1200网络处理器的硬件体系结构。最后介绍了一种基于IXP1200网络处理器的边缘路由器实现方案。     

基于位置的社交网络研究综述

当今,对线上社交网络的研究和线下人们在物理世界中活动的研究都已经很成熟,将线上社交网络和线下物理世界结合起来的异构网络成为研究热点,基于位置的社交网络是通过位置信息理解用户行为和偏好的新型异构网络。本文从服务和应用的角度对基于位置的社交网络的研究情况进行分析总结,为未来对异构网络进行深入研究以及在基于位置的社交网络中提出新的应用奠定基础。最后,本文对基于位置的社交网络的研究情况进行总结与展望。     

基于社团结构的复杂网络抗毁性测度

综合复杂网络连通度和社团结构的抗毁性测度,提出了一种新的基于社团结构的复杂网络抗毁性测度,既考虑网络的整体效能,又联系了网络本身的社团结构性。另一方面,为了更加有效地攻击网络的社团,提出一种基于社团的选择性攻击方式,移除较少的节点就使网络中的社团崩溃。通过仿真分析表明,基于社团的复杂网络抗毁性测度更加全面客观地衡量了网络的抗毁性,基于社团的选择性攻击更加有效地破坏了网络的社团结构性。     

基于加权网络的僵尸网络传播模型研究

主要研究不同网络拓扑下的僵尸网络Botnet传播行为,重点研究基于两种加权网络下的僵尸网络传播特性。基于经典加权网络(BBV网络)的演化规则,在随机权重的基础上,提出随机增量的加权演化模型;通过模型仿真,发现基于随机加权的网络与其它两种网络拓扑下僵尸网络相比,表现出更强的健壮性,这与建模时的理论分析完全一致。仿真结果表明,与无标度网络下的传播模型相比,基于加权网络的传播模型更符合僵尸网络在实际网络中的传播特性。     

Effects of 3D displays: A comparison between shuttered and polarized displays

The current study investigates the effects of 3D displays (shuttered display vs. polarized display). People experienced superior fidelity and brightness when they watched 2D still images on a shuttered display, rather than on a polarized display. Conversely, people experienced greater brightness when they watched 3D still images on a polarized display, rather than on a shuttered display. Second, people were able to read a smaller font or characters on a shuttered display than on a polarized display. Third, people noticed flickering on a shuttered display when they watched 3D images. Fourth, people experienced greater brightness when they watched 3D moving images on a shuttered display, rather than on a shuttered display. The perceived brightness of the screen positively correlated with enjoyment, content satisfaction, and 3DTV satisfaction when the viewers watched a 3D movie. The flickering, on the other hand, has a negative correlation with enjoyment and 3DTV satisfaction.     

The Effect of Webpage Complexity and Banner Animation on Banner Effectiveness in a Free Browsing Task

The effectiveness of banner advertisements has gained considerable attention among academics and practitioners. Despite the research progress in investigating the effect of banner properties (e.g., animation and location) on user perception and behavior, there is still a very limited understanding of how the properties of a banner and the surroundings of a website on which a banner is displayed can jointly influence its effectiveness. This study used eye-tracking technology to investigate the impact of banner animation and webpage complexity on users’ attention and memory performance. The results show that, during a free browsing task, an animated banner can attract earlier, greater, and more frequent attention from users and lead to better memory performance than a static one. Similarly, a banner on a low-complexity webpage also attracts earlier and more frequent attention among users and results in better memory performance than that on a high-complexity webpage. One implication is that an animated banner or a banner on a low-complexity webpage can provide a promising means of attracting users’ attention and enhancing their memory of the banners. Moreover, this study finds an interaction effect between banner animation and webpage complexity on the time to ?rst ?xation on a banner, but not on the total numbers or duration of fixations on a banner, or users’ memory performance. The finding highlights that an animated banner on a low-complexity website can be the most effective means to shorten the time to first fixation and quickly attract users’ attention. However, it cannot be deemed the most effective in generating greater and more frequent fixations on a banner, or leading to superior user memory performance.     

Cooperative caging and transport using autonomous aquatic surface vehicles

We present a study on the cooperative control of two autonomous surface vehicles performing a caging and transport mission on the water surface. The two vehicles, connected to each other by means of a floating flexible rope, are required to capture a floating target from a given location, and transport it to a designated position. We focus on the coordination and control strategy to meet these requirements, and on its implementation on two under-actuated vehicles. We describe a multi-layered control architecture which achieves the goal, followed by simulation studies and field experiments with the two vehicles caging and transporting a floating target on the surface of a lake.     

Experimental studies on passive dynamic bipedal walking

Passive dynamic walking is a gait developed, partially or in whole, by the energy provided by gravity. The research on passive dynamic bipedal walking helps create an understanding of walking mechanics. Moreover, the experimental passive dynamic research provides a base to compare and validate computer simulation results. An improved kneed bipedal walking mechanism was designed and built to study the passive gait patterns. The first aim of this study is to determine the equivalency of testing a passive dynamic biped walker on a treadmill to testing on a ramp. Based on the small difference between the gait patterns measured on the two test platforms, testing on a treadmill was found equivalent to testing on a ramp. Gait measurements were then conducted on the treadmill to evaluate the effects of the treadmill inclination angle, mass distribution of the biped, and the length of flat feet on the gait pattern. Results show that most of these parameters had significant effects on the step length, step period and hip velocity of the passive walker. Our experimental results are also compared with previous experimental results.     

MATLAB在图象数字水印技术研究中的应用

数字水印技术作为数字媒体版权保护的有效办法,涉及到多个学科,迫切需要一种强大的研究工具.MATLAB以其自身具有的优势,正好可以成为研究数字水印的一种有效工具.本文是在作者编程研究图象数字水印的背景基础上,总结MATLAB在其中的应用.为了证明MATLAB的高效性,作者在本文结尾部分给出一个用MATLAB实现基于Chebyshev混沌信号的扩频图象数字水印实例.     

Two criteria in multiple decision making

The author obtains two solutions for the uncertainty problem in a multistep decision-making problem for a wide class of preference choice rules in a decision-making system. They are based on the principles of guaranteed and best results, respectively, with the criteria in the form of preferences on decisions defined by an explicitly specified utility function, which parametrically depends on a convex statistical regularity on the set of states and on the utility function on the consequences, which is determined to within a positive linear transformation.     

相关集的数据关联描述及实例讨论

为了讨论数据关联问题,按层次对数据集进行了粒化,引入了每一粒的相关集,产生了与相关集类关联的分层粒化结构,并称之为粒化树。进而以同一数据集上的两棵粒化树为结构支撑,完成了对数据关联的定义,使相关集之间数据的关联得以数值化表示,形成了数据关联的数值描述方法。对此的研究确定了数据关联的等价条件,以此为依托并通过实例探究了数据关联的相关性质,讨论了关联的紧密程度、数据的粒化等同、关联的相互比较等数值化的处理方法。同时为实例的讨论提供了算法编程的基础,表明了数据关联研究的实际意义。     

MEMS packaging process by film transfer using an anti-adhesive layer

A low cost and low temperature thin film packaging process based on the transfer of an electroplated Nickel 3D cap is proposed. This process is based on adhesion control of a thick molded cap Ni film on the carrier wafer by using a plasma deposited fluorocarbon film, on mechanical debonding and on adhesive bonding of the microcaps on the host wafer with BCB sealing rings. Mechanical characterizations show that the transferred microcaps have a high stiffness, a low stress and a high adhesion. Because this process is simple and only involves a low temperature (250°C) heating of the host wafer, it is highly versatile and suitable for the encapsulation of micro and nano devices, circuits and systems elaborated on a large range of substrate materials.     

Rule-based optimization of combustion in multiple-burner furnaces and boiler plants

Rules for adjusting the air inlet valves to each of a number of burners with a common flue, depending on the concentrations of oxygen and carbon monoxide in that flue, were elicited from experts and coded in PROLOG. The program was tested on a PROLOG simulation of a multiple-burner installation. It was then run on a twelve-burner zone of a 108-burner furnace on a continuous annealing line for rolled steel. A system which learns its own rules is being developed, and will be tested against the rule-based system on a multiple-burner boiler plant.     

Gait generation and control for biped robots with underactuation degree one

The paper develops a unified feedback control law for n degree-of-freedom biped robots with one degree of underactuation so as to generate periodic orbits on different slopes. The periodic orbits on different slopes are produced from an original periodic orbit, which is either a natural passive limit cycle on a specific slope or a stable periodic walking gait on level ground generated with active control. First, inspired by the controlled symmetries approach, a general result on gait generation on different slopes based on a periodic orbit on a specific slope is obtained. Second, the time-scaling control approach is integrated to reproduce geometrically same periodic orbits for biped robots with one degree of underactuation. The degree of underactuation is compensated by one degree-of-freedom in the temporal evolution that scales the original periodic orbit. Necessary and sufficient conditions are investigated for the existence and stability properties of periodic orbits on different slopes with the proposed control law. Finally, the proposed approach is illustrated by two kinds of underactuated biped robots: one has a passive gait on a specific ground slope and the other does not have a natural passive gait.